The major focus of this research is to elucidate the molecular lesions in the neoplastic cell that may be related to the autonomous control of adrenal neoplasia. Specifically, we are analyzing at the molecular level the regulatory role of cyclic GMP and cyclic AMP in an intact fasciculata cell and are then comparing these results with those obtained in its counterpart, the malignant adrenal cell. Such comparative studies have demonstrated a unique autophosphorylating protein kinase (AUT-PK) and membrane alpha-adrenergic coupled guanylate cyclase systems in the adrenocortical carcinoma cells. In addition, we have provided evidence for a cyclic nucleotide-independent protein kinase in adrenocortical cells. Two tumor enzymes, AUT-PK 85 and AUT-PK 134, have been purified to homogeneity. The project is designed to further characterize the AUT-PK 85 and AUT-PK 134 enzymes and elucidate their mechanisms of regulation by adrenal neoplasia. The homogeneous enzymes will be characterized by standard physicochemical techniques. They will be fragmented and their cyclic AMP-binding and phosphorylated domains will be compared with each other and with the cyclic AMP-dependent protein kinase. The tumor alpha-adrenergic receptors will be solubilized and purified to homogeneity by affinity chromatography. The homogeneous receptors will be characterized. Ultimately, antibodies will be developed against these receptors and their development will be correlated with malignancy. The hypothesis that cyclic GMP-dependent protein kinase is absent in adrenocortical carcinoma cells will be evaluated.